randomdev.c revision 254147
162053Smarkm/*- 2254147Sobrien * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com> 3128059Smarkm * Copyright (c) 2000-2004 Mark R V Murray 462053Smarkm * All rights reserved. 562053Smarkm * 662053Smarkm * Redistribution and use in source and binary forms, with or without 762053Smarkm * modification, are permitted provided that the following conditions 862053Smarkm * are met: 962053Smarkm * 1. Redistributions of source code must retain the above copyright 1062053Smarkm * notice, this list of conditions and the following disclaimer 1162053Smarkm * in this position and unchanged. 1262053Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1362053Smarkm * notice, this list of conditions and the following disclaimer in the 1462053Smarkm * documentation and/or other materials provided with the distribution. 1562053Smarkm * 1662053Smarkm * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1762053Smarkm * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1862053Smarkm * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1962053Smarkm * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 2062053Smarkm * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2162053Smarkm * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2262053Smarkm * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2362053Smarkm * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2462053Smarkm * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2562053Smarkm * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2662053Smarkm * 2762053Smarkm */ 2862053Smarkm 29119418Sobrien#include <sys/cdefs.h> 30119418Sobrien__FBSDID("$FreeBSD: head/sys/dev/random/randomdev.c 254147 2013-08-09 15:31:50Z obrien $"); 31119418Sobrien 3262053Smarkm#include <sys/param.h> 3362053Smarkm#include <sys/systm.h> 3476166Smarkm#include <sys/bus.h> 3562053Smarkm#include <sys/conf.h> 3676166Smarkm#include <sys/fcntl.h> 3774771Smarkm#include <sys/filio.h> 3862053Smarkm#include <sys/kernel.h> 3974072Smarkm#include <sys/kthread.h> 4076166Smarkm#include <sys/lock.h> 4162053Smarkm#include <sys/malloc.h> 42129876Sphk#include <sys/module.h> 4376166Smarkm#include <sys/mutex.h> 4467112Smarkm#include <sys/poll.h> 45164033Srwatson#include <sys/priv.h> 4683366Sjulian#include <sys/proc.h> 4770834Swollman#include <sys/selinfo.h> 4876166Smarkm#include <sys/uio.h> 4976166Smarkm#include <sys/unistd.h> 5074072Smarkm 5162053Smarkm#include <machine/bus.h> 5274072Smarkm#include <machine/cpu.h> 5362053Smarkm 5474072Smarkm#include <dev/random/randomdev.h> 5562053Smarkm 56122871Smarkm#define RANDOM_MINOR 0 5762053Smarkm 58128059Smarkmstatic d_close_t random_close; 59128059Smarkmstatic d_read_t random_read; 60128059Smarkmstatic d_write_t random_write; 61128059Smarkmstatic d_ioctl_t random_ioctl; 62128059Smarkmstatic d_poll_t random_poll; 63122871Smarkm 6462053Smarkmstatic struct cdevsw random_cdevsw = { 65128059Smarkm .d_version = D_VERSION, 66128059Smarkm .d_close = random_close, 67128059Smarkm .d_read = random_read, 68128059Smarkm .d_write = random_write, 69128059Smarkm .d_ioctl = random_ioctl, 70128059Smarkm .d_poll = random_poll, 71128059Smarkm .d_name = "random", 7262053Smarkm}; 7362053Smarkm 74254147Sobrienstatic struct random_adaptor *random_adaptor; 75254147Sobrienstatic eventhandler_tag attach_tag; 76254147Sobrienstatic int random_inited; 7774072Smarkm 78254147Sobrien 7962053Smarkm/* For use with make_dev(9)/destroy_dev(9). */ 80130585Sphkstatic struct cdev *random_dev; 8162053Smarkm 82254147Sobrien/* Used to fake out unused random calls in random_adaptor */ 83128059Smarkmvoid 84128059Smarkmrandom_null_func(void) 8574072Smarkm{ 8674072Smarkm} 8762053Smarkm 8891600Smarkm/* ARGSUSED */ 8962053Smarkmstatic int 90130585Sphkrandom_close(struct cdev *dev __unused, int flags, int fmt __unused, 91128059Smarkm struct thread *td) 9269172Smarkm{ 93164033Srwatson if ((flags & FWRITE) && (priv_check(td, PRIV_RANDOM_RESEED) == 0) 94128059Smarkm && (securelevel_gt(td->td_ucred, 0) == 0)) { 95254147Sobrien (*random_adaptor->reseed)(); 96254147Sobrien random_adaptor->seeded = 1; 97185254Scperciva arc4rand(NULL, 0, 1); /* Reseed arc4random as well. */ 9883976Srwatson } 99128321Smarkm 100128059Smarkm return (0); 10169172Smarkm} 10269172Smarkm 10391600Smarkm/* ARGSUSED */ 10469172Smarkmstatic int 105130585Sphkrandom_read(struct cdev *dev __unused, struct uio *uio, int flag) 10662053Smarkm{ 107128059Smarkm int c, error = 0; 108128367Smarkm void *random_buf; 10962053Smarkm 110128059Smarkm /* Blocking logic */ 111254147Sobrien if (!random_adaptor->seeded) 112254147Sobrien error = (*random_adaptor->block)(flag); 113128059Smarkm 114128059Smarkm /* The actual read */ 115128059Smarkm if (!error) { 116128367Smarkm 117128367Smarkm random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 118128367Smarkm 119128059Smarkm while (uio->uio_resid > 0 && !error) { 120128059Smarkm c = MIN(uio->uio_resid, PAGE_SIZE); 121254147Sobrien c = (*random_adaptor->read)(random_buf, c); 122128059Smarkm error = uiomove(random_buf, c, uio); 123128059Smarkm } 124128367Smarkm 125128367Smarkm free(random_buf, M_TEMP); 126128367Smarkm 12767286Speter } 128128151Smarkm 129128059Smarkm return (error); 13062053Smarkm} 13162053Smarkm 13291600Smarkm/* ARGSUSED */ 13362053Smarkmstatic int 134130585Sphkrandom_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 13562053Smarkm{ 136128059Smarkm int c, error = 0; 137128367Smarkm void *random_buf; 13862053Smarkm 139128367Smarkm random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 140128367Smarkm 14162053Smarkm while (uio->uio_resid > 0) { 142128059Smarkm c = MIN((int)uio->uio_resid, PAGE_SIZE); 14362765Smarkm error = uiomove(random_buf, c, uio); 14462053Smarkm if (error) 14562053Smarkm break; 146254147Sobrien (*random_adaptor->write)(random_buf, c); 14762053Smarkm } 148128321Smarkm 149128367Smarkm free(random_buf, M_TEMP); 150128367Smarkm 151128059Smarkm return (error); 15262053Smarkm} 15362053Smarkm 15491600Smarkm/* ARGSUSED */ 15562053Smarkmstatic int 156130585Sphkrandom_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 15791600Smarkm int flags __unused, struct thread *td __unused) 15865686Smarkm{ 159128059Smarkm int error = 0; 160128059Smarkm 16174771Smarkm switch (cmd) { 162128059Smarkm /* Really handled in upper layer */ 16374771Smarkm case FIOASYNC: 16474771Smarkm case FIONBIO: 165128059Smarkm break; 16674771Smarkm default: 167128059Smarkm error = ENOTTY; 16874771Smarkm } 169128059Smarkm return (error); 17065686Smarkm} 17165686Smarkm 17291600Smarkm/* ARGSUSED */ 17365686Smarkmstatic int 174130585Sphkrandom_poll(struct cdev *dev __unused, int events, struct thread *td) 17567112Smarkm{ 176128059Smarkm int revents = 0; 17767112Smarkm 17867112Smarkm if (events & (POLLIN | POLLRDNORM)) { 179254147Sobrien if (random_adaptor->seeded) 18067112Smarkm revents = events & (POLLIN | POLLRDNORM); 18167112Smarkm else 182254147Sobrien revents = (*random_adaptor->poll) (events,td); 18367112Smarkm } 184128059Smarkm return (revents); 18567112Smarkm} 18667112Smarkm 187254147Sobrienstatic void 188254147Sobrienrandom_initialize(void *p, struct random_adaptor *s) 189254147Sobrien{ 190254147Sobrien if (random_inited) { 191254147Sobrien printf("random: <%s> already initialized\n", 192254147Sobrien random_adaptor->ident); 193254147Sobrien return; 194254147Sobrien } 195254147Sobrien 196254147Sobrien random_adaptor = s; 197254147Sobrien 198254147Sobrien (s->init)(); 199254147Sobrien 200254147Sobrien printf("random: <%s> initialized\n", s->ident); 201254147Sobrien 202254147Sobrien random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw, 203254147Sobrien RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random"); 204254147Sobrien make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 205254147Sobrien 206254147Sobrien /* mark random(4) as initialized, to avoid being called again */ 207254147Sobrien random_inited = 1; 208254147Sobrien} 209254147Sobrien 21091600Smarkm/* ARGSUSED */ 21167112Smarkmstatic int 21291600Smarkmrandom_modevent(module_t mod __unused, int type, void *data __unused) 21362053Smarkm{ 214128059Smarkm int error = 0; 21565686Smarkm 216128059Smarkm switch (type) { 21762053Smarkm case MOD_LOAD: 218254147Sobrien random_ident_hardware(&random_adaptor); 21971037Smarkm 220254147Sobrien if (random_adaptor == NULL) { 221254147Sobrien printf( 222254147Sobrien "random: No random adaptor attached, postponing initialization\n"); 223254147Sobrien attach_tag = EVENTHANDLER_REGISTER(random_adaptor_attach, 224254147Sobrien random_initialize, NULL, EVENTHANDLER_PRI_ANY); 225254147Sobrien } else { 226254147Sobrien random_initialize(NULL, random_adaptor); 227254147Sobrien } 22871037Smarkm 229128059Smarkm break; 23074072Smarkm 23162053Smarkm case MOD_UNLOAD: 232254147Sobrien if (random_adaptor != NULL) { 233254147Sobrien (*random_adaptor->deinit)(); 234254147Sobrien destroy_dev(random_dev); 235254147Sobrien } 236254147Sobrien /* Unregister the event handler */ 237254147Sobrien if (attach_tag != NULL) { 238254147Sobrien EVENTHANDLER_DEREGISTER(random_adaptor_attach, 239254147Sobrien attach_tag); 240254147Sobrien } 24174072Smarkm 242128059Smarkm break; 243122871Smarkm 24462053Smarkm case MOD_SHUTDOWN: 245128059Smarkm break; 24662053Smarkm 247132199Sphk default: 248132199Sphk error = EOPNOTSUPP; 249132199Sphk break; 250132199Sphk 25162053Smarkm } 252128059Smarkm return (error); 25362053Smarkm} 25462053Smarkm 25562053SmarkmDEV_MODULE(random, random_modevent, NULL); 256133036SmarkmMODULE_VERSION(random, 1); 257